ESO observes supernova in 3D

Emma Woollacott, 4th August 2010

Astronomers using ESO’s Very Large Telescope have for the first time been able to see a stellar explosion in 3D.

The blast was powerful, and concentrated in one particular direction, implying that the supernova must have been very turbulent, and supporting the latest computer models.

Supernova 1987A in the nearby Large Magellanic Cloud was seen in 1987 - the first naked-eye supernova to be observed for nearly four hundred years.

Because it's relatively close, it's been a 'bonanza for astrophysicists', says ESO. It's provided several 'firsts', such as the detection of neutrinos from the collapsing inner stellar core, the direct observation of the radioactive elements produced during the blast and observation of the formation of dust in the supernova.

And now, the VLT's Spectrograph for Integral Field Observations in the Near Infrared - Sinfoni - has helped create the first-ever 3D reconstruction of the central parts of the exploding material.

The first material to be ejected from the explosion travelled at an astounding 100 million kilometers per hour - but has still taken 10 years to reach a previously existing ring of gas and dust.

The images also show another wave of material travelling ten times more slowly, and being heated by radioactive elements created in the explosion.

"We have established the velocity distribution of the inner ejecta of Supernova 1987A," says lead author Karina Kjær.

"Just how a supernova explodes is not very well understood, but the way the star exploded is imprinted on this inner material. We can see that this material was not ejected symmetrically in all directions, but rather seems to have had a preferred direction. Besides, this direction is different to what was expected from the position of the ring."

The asymmetry was predicted by some recent computer models of supernovae, which found that large-scale instabilities take place during the explosion. The new observations are the first direct confirmation.